How can we improve Duplicate Remover or Duplicate Killer?

Improve the upgade process. I bought Duplicate Killer in October with the imprssion that a years worth of upgrades was included. Now barely

Clean up the upgrade process. I bought a copy of Duplicate Killer in October with the impression that a years worth of upgrades were included. Now, barely 4 months later I am being pressured to upgrade again, apparently for full price even though the site says a 30 per cent discount. And how do I get back to my old copy of DK? I does not seem easy.